SMS Group Microsoft Azure Administrator Interview Questions and Answers

SQL aggregation functions perform calculations on multiple rows of a single column of a table.

• Aggregation functions include COUNT, SUM, AVG, MAX, and MIN.

• They are used with the SELECT statement to retrieve data from a table.

• Examples: SELECT COUNT(*) FROM customers; SELECT AVG(price) FROM products;

• Aggregate functions can also be used with the GROUP BY clause to group data by one or more columns.

Join queries are used to combine data from two or more tables based on a related column.

• Use the JOIN keyword followed by the name of the table you want to join.

• Specify the columns you want to select from each table.

• Use the ON keyword to specify the column(s) that the tables should be joined on.

• There are different types of joins: INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN.

• Example: SELECT customers.name, orde...read more

SQL is a programming language used to manage and manipulate relational databases.

• SQL stands for Structured Query Language

• It is used to create, modify, and query databases

• Common commands include SELECT, INSERT, UPDATE, and DELETE

• Example: SELECT * FROM customers WHERE age > 18;

A constructor is a special method used to initialize objects in a class.

• Constructors have the same name as the class they belong to.

• They are called automatically when an object is created.

• Constructors can take parameters to set initial values.

• They can be overloaded to provide multiple ways of initializing objects.

Class and object are fundamental concepts in object-oriented programming. Method overloading and method overriding are two ways to achieve polymorphism.

• A class is a blueprint or template for creating objects that encapsulate data and behavior.

• An object is an instance of a class that has its own state and behavior.

• Method overloading is when multiple methods in a class have the same name but different parameters.

• Method o...read more

SQL subquery is a query within another query used to retrieve data from one or more tables.

• Subqueries are enclosed in parentheses and placed within the WHERE or HAVING clause of the outer query.

• They can be used to filter, sort, or aggregate data based on the results of the subquery.

• Subqueries can also be used in the SELECT statement to retrieve a single value or set of values.

• Example: SELECT * FROM employees WHERE depa...read more

A complex query is a query that involves multiple tables, conditions, and/or functions.

• Start by identifying the tables involved in the query

• Determine the conditions that need to be met using WHERE clause

• Use JOIN to combine tables if necessary

• Use aggregate functions like COUNT, SUM, AVG, etc. to perform calculations

• Use subqueries to break down complex queries into smaller parts

• Test the query and refine as necessary